On the characteristics of a plasma arc heater for a high enthalpy wind tunnel

Abstract

A 1MW segmented-constricted arc heater test facility was developed in order to investigate its fundamental characteristics. Various configurations of an arc heater and electrodes are prepared. Constrictor diameter is 25.4 mm. Total mass flow rate of air and argon is 25 g/s, current is 610 A. The heater L/D ratio experimentally investigated was 16, 20, and total enthalpy was 10.6 MJ/kg and 16.3 MJ/kg for above two L/D conditions. Measured voltage and total enthalpy agreed with the ARCFLO-II prediction. From the ARCFLO-II prediction, total enthalpy is 20 MJ/kg and better flow uniformity is obtained if the L/D ratio is 40. Erosion rates for a upstream tungsten cathode and a downstream copper anode were measured from 1.2 atm to 4.6 atm. As pressure increases, erosion rate increases. The erosion rates for a cathode and an anode of 4.6 atm condition were 0.04 u- g/C and 1.4 u. g/C, respectively. For an anode, erosion rate is proportional to the heat flux of an arcfoot.